/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.hadoop.hive.ql.optimizer.calcite.translator.opconventer;

import org.apache.calcite.rel.RelNode;
import org.apache.hadoop.hive.ql.optimizer.calcite.translator.opconventer.HiveOpConverter.OpAttr;
import org.apache.hadoop.hive.ql.parse.SemanticException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Abstract ancestor of all the visitors.
 */
abstract class HiveRelNodeVisitor<T extends RelNode> {
  protected static final Logger LOG = LoggerFactory.getLogger(HiveRelNodeVisitor.class);

  protected final HiveOpConverter hiveOpConverter;

  HiveRelNodeVisitor(HiveOpConverter hiveOpConverter) {
    this.hiveOpConverter = hiveOpConverter;
  }

  abstract OpAttr visit(T hiveRelNode) throws SemanticException;
}
